Patent US3937675A successfully refreshed from Google Patents.
US3937675A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of textile waste formed of polyester and cellulosic fibers
Assignee: Textile Res Inst
•
Filing: 1974-11-18
•
Granted: 1976-02-10
•
Expires: 1994-11-18
Abstract
Abstract Textile wastes formed of blended cellulose and polyester fibers are treated with a mineral acid agent, such as sulfuric acid, under conditions which serve to hydrolyze the cellulose and convert it to a form which is readily removed from the polyester fibers while leaving the polyester fiber substantially unaffected. The cellulosic material is recovered in the form of "fibrets" adapted for use as such or for treatment in producing other cellulosic compounds whereas the polyester fiber recovered may be garnetted for reuse in either spun yarn manufacture or in nonwoven processes.
Inventors
- 👤 Irving Gruntfest
- 👤 Rudolph Turner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:50
CPC Classifications
D; D06; D06Q; D06Q1/00; D06Q1/02; C; C08; C08J; C08J11/00; C08J11/04; Y; Y02; Y02P; Y02P20/00; Y02P20/141; Y02P20/143; Y02W; Y02W30/00; Y02W30/50; Y02W30/62
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
75 words
A method for recovering polyester fibers and cellulosic material in useful form from textile wastes containing the same which comprises the steps of treating the waste with an aqueous solution of a mineral acid under reaction conditions which serve to convert the cellulose to a substantially non-fibrous condition while leaving the polyester fibers substantially unaffected, separating the liquid and cellulosic reaction product from the polyester fibers and thereafter separating said reaction product from said liquid.
Claim 2
Independent Claim
75 words
A method for recovering polyester fibers and cellulosic material in useful form from textile wastes containing the same which comprises the steps of treating the waste with an aqueous solution of a mineral acid under reaction conditions which serve to convert the cellulose to a substantially non-fibrous condition while leaving the polyester fibers substantially unaffected, separating the liquid and cellulosic reaction product from the polyester fibers and thereafter separating said reaction product from said liquid.
Claim 3
Dependent Claim
14 words
A method as defined in claim 1 wherein the mineral acid is sulfuric acid.
Claim 4
Dependent Claim
34 words
A method as defined in claim 1 wherein the mineral acid is in the form of an aqueous solution containing at least 5% and not more than about 35% by weight of sulfuric acid.
Claim 5
Dependent Claim
22 words
A method as defined in claim 3 wherein said reaction is carried out at a temperature of from about 80°C to 100°C.
Claim 6
Independent Claim
81 words
A method of recovering polyester fibers and cellulosic material in useful form from textile wastes containing the same which comprises immersing said waste in an aqueous solution containing from about 5% to 35% by weight of sulfuric acid, agitating said solution and waste for a period of from about 15 minutes to one hour at a temperature of from about 80°C to 100°C, separating the polyester fiber from said solution, and thereafter separating the resulting cellulosic reaction product from said solution.
Claim 7
Independent Claim
81 words
A method of recovering polyester fibers and cellulosic material in useful form from textile wastes containing the same which comprises immersing said waste in an aqueous solution containing from about 5% to 35% by weight of sulfuric acid, agitating said solution and waste for a period of from about 15 minutes to one hour at a temperature of from about 80°C to 100°C, separating the polyester fiber from said solution, and thereafter separating the resulting cellulosic reaction product from said solution.
Claim 8
Dependent Claim
29 words
A method as defined in claim 5 wherein the polyester fiber is washed with water to separate the cellulosic reaction product therefrom and the polyester fiber is thereafter garnetted.
Claim 9
Dependent Claim
33 words
A method as defined in claim 5 wherein the cellulosic reaction product is separated from the polyester fibers by washing the fiber with a liquid and is recovered from the resulting wash liquid.
Claim 10
Dependent Claim
24 words
A method as defined in claim 7 wherein the wash liquid is concentrated and thereafter freeze dried to obtain the cellulosic reaction product therefrom.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-09 | 1979-08-11 | 1980-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-09 | 1983-08-11 | 1984-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-09 | 1987-08-11 | 1988-02-10 | $7700.00 | Window Closed / Lapsed |